What to Look for in an AR-15 Bolt & BCG?

[Will_Power]

Putting together the final odds and ends for my first high-ish quality precision AR-15, but am kind of stumped about the bolt and bolt carrier. From what I've read, having a matching bolt to your barrel doesn't ultimately have all that much of an effect on things, compared to a quality barrel, trigger, and set of glass, but what else do I need to look for?

I've read in numerous places the carrier needs to be "properly staked," but to be honest, I couldn't tell you what exactly that means or what to look for in that regard.

Other than that, from what I've read, it seems that one mil-spec auto BCG is the same as any other and the ones with slick coating (NiB and the like) aren't necessary as long as you intelligently run your gun wet.

Is there anything important I'm missing here, or should I stop overthinking this?

 

[Jaytrigger]

Depends on your setup and what its used for. Low mass heavy mass or middle ground paired with a heavy buffer, low mass buffer and your Gas intake length all play in sync with each other to the indiviual users preference.

If you plan an SBR build that goes between Suppressed and Non Suppressor you may want adjustable gas block as well. It all effects accuracy (timing release of gas behind the bullet into the intake and how much)

Need specifics as to what you are intending for the use of the rifle your building and what type of Grain and Bullet shape your using.

 

[Will_Power]

Depends on your setup and what its used for. Low mass heavy mass or middle ground paired with a heavy buffer, low mass buffer and your Gas intake length all play in sync with each other to the indiviual users preference.

If you plan an SBR build that goes between Suppressed and Non Suppressor you may want adjustable gas block as well. It all effects accuracy (timing release of gas behind the bullet into the intake and how much)

Need specifics as to what you are intending for the use of the rifle your building and what type of Grain and Bullet shape your using.

I'm putting together a precision AR for marksmanship training and occasional predator/varmint hunting.

WOA's 20" SDM-R barrel, rifle length buffer and Magpul A2 stock, and a Giesselle SSA-E trigger group.

More than likely will use the Vortex PST 2.5-10x32 FFP scope with MRAD reticle.

Not planning on using an adjustable gas block; don't need to tweak the recoil impulse for three-gun or anything. Likewise, I won't be running suppressed or with a muzzle break; I'm going with a flash hider instead.

 

[Jaytrigger]

I would then stay along the standard but Quality BCG then. Young Manufacturing,BCM, WMD, Wilson Combat, JP to name a few. Tweeking also isnt just for 3 gun. It helps with Follow up and with a Precision AR tweek it will dramatically help perfect your form. It is kinda a learn as you go because what works for me and my hold (different body structure than you) maybe different from you.
Long range on varmit may require a follow up shot if trying to get multiple varmit before the take off. I use a 6.5 Grendel and a 223 wylde chamber.

 

[Will_Power]

I would then stay along the standard but Quality BCG then. Young Manufacturing,BCM, WMD, Wilson Combat, JP to name a few. Tweeking also isnt just for 3 gun. It helps with Follow up and with a Precision AR tweek it will dramatically help perfect your form. It is kinda a learn as you go because what works for me and my hold (different body structure than you) maybe different from you.
Long range on varmit may require a follow up shot if trying to get multiple varmit before the take off. I use a 6.5 Grendel and a 223 wylde chamber.

What are your thoughts on this Fulton Armory set?

Staked gas key, HP/MP tested and marked, mil-spec. It seems to be workable and it's fifty bucks cheaper than the complete setups from BCM, LMT, etc. Am I missing something?

Likewise, JoeBobOutfitter's has an inhouse complete BCG that's MP testing and has the gas key staked, and it's cheaper still at $120.

Edit: I'm certainly not opposed to spending the money on quality parts, as long as I am paying for quality and not a brand name. That's why I'm trying to educate myself here.

 

[KUSA]

Just get this and be done with it. Palmetto State Armory 5.56 Premium Full Auto Bolt Carrier Group - AR-15 Parts Sale - AR-15

 

[dragbag]

Bolt Carrier Assembly, 5.56 NATO-Wilson Combat

 

[Oryx]

I would look for a bolt manufactured out of 9310 vs. the carpenter-158 steel for longer life expectancy, MP inspected. Most importantly that it headspaces correctly with your chamber.
Surface finish is a preference thing and weight can be used to tune recoil along with buffers, springs and adj gas blocks.

 

[Scaevola]

Let's see, BCG's that I've run and trusted -

Of course, BCM.
Wilson Combat - on the 12 days of Christmas sale, great buy.
PSA - not bad for the cost.
Stag - not bad either, upgraded extractor/spring/donut.
JoeBob's - Ran that in a 12.2" 300BLK, came with upgraded extractor kit and McFarland gas ring setup.

158C has been tried and true in AR bolts, so I stick with it. I do have 9310 bolts, but until I run one past 7500 rounds, I'm not entirely sold on them yet.

 

[Oryx]

The tests have already been done. Material properties are better suited.
Either one works fine.

 

[Joe Curnarski]

Bravo Company. Buy and don't look back.

 

[hewlett260]

BCM and Rainier Arms are both good. Currently running a Rainier NiB full auto carrier. So far no problems currently at 5800 rounds.

 

[MikeInUtah]

Regarding your question about properly staked bolt carrier: bolt carrier staking (comparison)
It shows some good pics to help explain it.

 

[tipper]

If you do not have a plan, it is just parts, parts is parts.

 

[BERTMAN77MK2]

A good Smith will properly headspace a bolt to min specs for you. I ordered all WOA
barrels with matched bolts, and any premium barrel can be had with a matched bolt.
Get a top tier BC and it will be properly staked.

 

[tipper]

parts is parts, an crap will show up because of the flow

 

[binnerscot]

I would just grab something of decent quality and shoot the piss out of it. Bolts and extractors are consumable parts and will be replaced.

There are a lot of decent quality BCGs out there. A Stag BCG for example is CMT, which makes lots of good stuff behind the scenes for lots of manufacturers. All those mentioned in this thread are good BCGs. I like nickel boron just because it cleans a little easier and is a nice finish, but I have a both and phosphate runs just fine (always has).

BCGs I have:

Bushy
CMT/Stag
PSA
Spikes NiB
WMD Nib-X
CMMG
Whatever came with a JSE upper I bought

All of them are GTG. The Bushmaster has some pretty light staking, but that one probably has the highest round count also (several thousand now) with no issues.

 

[rsilvers]

I would look for a bolt manufactured out of 9310 vs. the carpenter-158 steel for longer life expectancy, MP inspected. Most importantly that it headspaces correctly with your chamber.
Surface finish is a preference thing and weight can be used to tune recoil along with buffers, springs and adj gas blocks.

That is not true at all. I believe there are two reasons why 9310 is used by some makers:

1 - They think it is better (but they would be incorrect).
2 - They cannot afford the minimum lot size for C158.

If anyone does not believe me, call Carpenter and ask to talk to an applications engineer. They sell both materials so are not biased. C158 is better. 9310 is much easier for small companies to get so that is a benefit to them.

Beyond that, correct dimensions matter, MP does not matter at all, but correct shot peening and heat treatment matters a whole lot.

 

[Letzgoracin301]

I run a BCM and a young nm. They are both quality pieces.

Sent from my MB886 using Tapatalk

 

[MSTN]

LMT shot peened, proof round tested, MP-inspected bolt, fitted at 1.4646", Ionbond Diamondblack ("D/B") coated down to the gas rings. Young MFG National Match forged, then centerless ground, the hard chromed, then D/B coated bolt carrier with LMT internals, all D/B coated.